Telephone system.



PATENTED OGT 23, 1906.

W. W. DEAN. TELEPHONE SYSTEM. APPLIOATIONIILED DEO.23,1902.

THE "cums FETERSCL, WASHINGTON, v c.

off relay devices of prior systems.

UNITED STATES PATENT OFFICE.

ILLINOIS, ASSIGNOR TO KELLOGG OMPANY, OF CHICAGO, ILLINOIS, A

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Oct. 23, 1906.

Application filed December 23,1902. Serial No. 136,833.

T0 ctZZ whom it may concern:

Be it known that I, WILLIAM W. DEAN, a citizen of the United States ofAmerica, residing at Chicago, in the county of Cook and State-ofIllinois, have invented certain new and useful Improvements in TelephoneSystems, of which the following is a specification. My invention relatesto telephone systems of the common battery type, in which a singleelectromagnetic device serves the purpose of the plurality ofline-signaling and cut- In this system I preferably make use of aconsequent-pole relay or electromagnetic device for the control of theline-signal. A consequent-pole relay or other electromagnetic device isone in which two opposing windings are so arranged as not to neutralizeeach other, but so as to allow the lines of force to unite and leave theclosed magnetic circuit, and thus attract an armature placed in theproper position to be attracted by the consequent pole thus produced. Ipreferably arrange this device with a winding in each of the lineconductors, one of said windings being of high resistancesay onethousand ohmsand the other winding of low resis tance say one hundredohms but the number of turns in both windings are preferably made equal.When a call is made from the substation, the calling-current passesserially through the two windings; but since the turns are ,the sameboth windings produce equal fields of force, which instead ofneutralizing each other serve to attract the armature located adjacentthe consequent pole. When the call is answered by the operator,provision is made for shunting the highresistance of the consequent-poledevice by a lowwound supervisory relay or electromagnetic winding,preferably of one hundred ohms, and the paths of these relays, togetherwith the line resistance, is shunted by another relay or supervisoryelectromagnetic winding, which is preferably of one thousand ohmsresistance. Under these conditions the field of force pro-" duced by theone-thousand-ohm winding will be so much less duced by theone-hundred-ohm winding that no consequent pole is produced, or, moreproperly speaking, if formed will be displaced, so that the armaturewill not be attracted.

than the field of force pro,

In the accompanying drawing the figure represents in diagram a telephonesystem embodying my improvements.

The same reference characters indicate like parts throughout.

Two subscribers lines L and L extend from their respective substationsin two limbs 2 and 3 to the central ofiice. At the substation anysuitable apparatus suitable for common battery working or for otherworking may be provided, that shown consisting of a bell 4 and condenser5 of ordinary type, preferably in a permanent bridge of the line, and atransmitter 6 and receiver 7 in a normally open bridge adapted to beclosed by the switch-hook 8 when the receiver is removed therefrom.

At the central oflice the line is provided with preferably permanentlyconnected jacks J, J and J 3 in any suitable number, having their tipand sleeve contacts connected with the corresponding line conductors.Each line is also provided with a consequent-pole relay R, having aclosed magnetic circuit, as shown, and a high-resistance coil 9 woundupon one side of said metallic closed magnetic circuit and included inthe tip-line conductor, while the low-resistance winding 10 thereof iswound upon the other side of said closed magnetic circuit and isincluded in the sleeveconductor 8 of the telephone-line. The consequentpole is formed substantially at the point 11 by the equal and oppositemagnetic elds generated in the opposite sides of the closed magneticcircuit by the current flowing serially over the line and through saidwindings when a subscriber is calling the central ofiice. respond tosaid consequent pole and controls the local circuit of the line-signalS, preferably in the form of a small incandescent lamp. The tip-lineconductor is connected with a common limb 13, extending to the live poleof the central and common source of steady current, preferably of thestorage-battery ty e.

Flach operator at the central office is rovided with a plurality ofcord-circuits aving each a pair of plugs P and P having tip and sleevecontact surfaces adapted to register with the like contact-surfaces ofthe springjacks or connection-terminals of the tele- An armature 12 isarranged to phone-lines, and the tip-contacts of which are connectedtogether through the strands t and t and the condenser 0, while. thesleeve-contacts of the said plugs are inductively joined by means of theflexible strands s and s and the condenser 0 Supervisory relays r and rare connected across the answering end of the cord-circuit, relay 1'being preferably of low resistance, while the relay r is of high resistance, and an intermediate point of their bridge is joined by conductor15 with the live pole of the battery B. The relay r controls, throughits normally closed contacts, and the relay 7*, through its normallyopen contacts, the circuit of the supervisory signal S A similar pair ofrelays r and r are connected in a bridge 16 of the calling end of thecordcircuit, which bridge is joined by a suitable conductor 17 with thelive pole of the battery These relays control the local circuit of thesupervisory lamp S associated with the calling-plug P The continuity ofthe tipstrand t is controlled through the extra spring 18 of the relay rand normally connects the forward portion of said strand through themedium of conductor 19 with a high-resistance and high-impedancetest-relay W, the other pole of which is grounded. The operatorstransmitter 20 is located in a grounded conductor 21, containingretardation-coil 22 and leading to the common conductor 13 connectedwith thelivepole of said battery B. The primary winding of the operatorsinduction-coil 23 and a condenser c are placed in a shunt about thetransmitter 20, and the middle point of said shunt is adapted to begrounded by the operation of the said test-relay. The operatorsreceiver, the secondary of her induction-coil, and a suitable condenserare adapted to be placed in a bridge of the calling end of thecord-circuit by springs 24 of any suitable listeningkey.ringing-generator 25, having one pole grounded, is adapted to beconnected with either side of the calling end of the cordcircuit by theoperation of springs 26 or 27, the opposite side of the cord-circuitbeing at the same time grounded.

Taking up the receiver at the station A of the line L permits current toflow from the battery B at the central ofiice over conductor 13, throughthe coil 9 of the consequent-pole relay R, over the tip-conductor 2,through the substation devices back to the central office over conductor3 and through the lowresistance winding 10 of said relay to ground.Owing to the equal number of turns of wire upon the two sides of thesaid relay, the magnetic fields produced are equal and opposite, and aconsequent pole is formed at the point 11, which serves to attract thearmature 12, thereby closing the local circuit of the linesignal S toindicate the call of the waiting call the opsubscriber. In response tothe erator inserts the answering-plug P, thereby connecting thesupervisory relay 1 in parallel with the winding 9 of the relay R, whilethe relay r is connected in parallel or in shunt of the line resistance,which includes the said relay and winding 9 in parallel. In other words,the said relay r is connected in series with the winding 10 of the relayR. Under the conditions assumed-namely, that the windings 9 and 10 ofrelay R are respectively one thousand and one hundred ohms resistanceand the windings of r and r are likewise of one hundred and one thousandohms resistance-the following condition now exists: The field of forceproduced by the one-thousand-ohm winding, which is shunted by theone-hundred-ohm winding of r is much less than that produced by theone-hundred-ohm winding 10, through which flows all the current sent toline from the battery B. This results in either preventing the formationof a pole or in so displacing it in the closed magnetic circuit that thearmature 12 is freed and drops back to open a circuit of the line-lampThe supervisory signal S is not operated. as the relay 1" serves to openits circuit. Upon learning the subscriber wanted, the calling-plug P isemployed to test the condition of the said line. If idle, the test-ringsof the acks of the line are connected with the ground or with thegrounded pole of the battery, while the tip of the testing-plug isnormally likewise connected through the test-relay r, so that no flow ofcurrent results and the busy-click is not received. If the line is busy,however, the test-rings of the jacks are connected, through thesleeve-strand of the cordcircuit, with the live pole of the battery B,and the application of a grounded test-plug results in a flow of currentand the actuation of the test-relay, which, as before explained, causesa click in the operators receiver.

Assuming that the line is found idle, the calling-plug is inserted andthe ringingsprings 26 or 27 actuated to call the sub scriber D or C,Whose bells are grounded from the opposite line conductors. The portionof the ringing-current that escapes through the one Winding or the otherof the relay B does not operate the same for two reasons first, becausethe current is alternating in character and the relay may not readilyrespond thereto, and, second, because the field of force is closed anddoes not produce a pole opposite the armature. Should the subscriberrespond during ringing, a low-resistance return-path is completedthrough the opposite grounded key, the latter serving as a return-pathduring ringing in case the subscribers bell is connected in the metalliccircuit. After ringing and before the response of the subscriber currentflows from the battery B over the conductors 17 and 16, through thesleeve-relay r, and thence over the sleeve-strand s and through thewinding 10 of the relay R. The relay B does not re- ITO spond to thiscurrent owing to the closed magnetic circuit for the field of force; butthe relay It is actuated and closes the local circuit of the supervisorylamp S which is now lighted and completes the tip-line for conversation.During conversation the battery B furnishes current to the substationsfor trans mission purposes and for the operation of the various relays.At the termination of the conversation the subscribers hang up theirreceivers, thus opening the lines to current thereover, and the samecondition prevails with both lines as just explained in connec tion withthe line L after the calling of the subscriber and before his responsethat is,

current from the battery B is flowing through both sleeve supervisoryrelays and through the windings 10 of the relays R, the latter. relaysrefusing to operate owing to their closed metallic circuits, while theformer relays remain energized to direct current through the supervisorylamps. Upon noticing these signals the operator withdraws the plugs andrestores all parts to normal condition. With the resistances assumed theunbalancing fea ture of the said line-relays is sufliciently great up toa total line resistance of nearly one thousand ohms to-obtain asufficient and satisfactory operation of the said relays.

The electrical dimensions of the other apparatus may be that usuallyemployed or such as may be desired. The several grounds mentioned may beone and the same, orthe common oflice ground or common office return.The substation set shown is intended merely to be typical of any desiredsubstation outfit suitable for the purposes in hand.

Various modifications may be made in the system and apparatus, and I donot, therefore, wish to be limited in all respects and in all claims tothose so specifically shown and described.

I claim- 1. In a telephone system, the combination with atelephone-line, of a consequent-pole electromagnetic device for eachline, means for operating the same to establish contiguous poles of thesame polarity whereby a consequent pole is formed thereon to cause asignal at the central office, and means to pre- Vent the formation ofsuch pole when a connection is established with a line to render thesignal inoperative, substantially as described.

2. In a telephone system, the combination with a telephone-line, of aconsequent-pole relay for the line, a signal controlled by said relay,means for actuating said relay controlled from the substation toestablish a consequent pole thereon between contiguous poles thereof ofthe same polarity, said consequent pole being adapted to cause a call atthe central office, and means for rendering said relay inoperative whena connection is established with the line to retire or prevent theoperation of the said signal, substantially as described.

3. In a telephone system, the combination with a telephone-line, aline-signaling device therefor, means controlled from the substation forestablishing a consequent pole on said device, and means for shiftingsaid pole upon the establishment of a connection with .the line,substantially as described.

4. In a telephone system, the combination with a telephone-line, of anelectromagnetic signaling device associated therewith having a closedmagnetic circuit, means for establishing a conse uent magnetic pole atone portion of said closed magnetic circuit, an armature arranged to beattracted by said pole, and means for rendering said device inoperativeto cause it to release the armature or fail to attract the same,substantially as described.

5. In a telephone system, the combination with a telephone-line, of aline-signaling device therefor having a closed magnetic circuit and twowindings of different resistances but capable of producing equal andopposite magnetic effects when traversed by current in the line at thetime the subscriber is calling the central ofiice, a cord-circuit toestablish connections with the line, and means operated when aconnection is established by said cord-circuit for causing said windingsto produce unlike effects, substantially as described.

6. Ina telephone system, the combination with a telephone-line, of aline-signaling device therefor having a closed magnetic circuit and twowindings one in each side of the line and in the path of currentthereover when the subscriber is calling the central ofiice, means tocause said windings to produce equal and opposite effects when traversed by such calling-currents so as to establish .a consequent poleupon said magnetic circuit, an armature to be attracted by said pole andcontrolling a suitable line-signal, a cord-circuit to establishconnections with the line, supervisory apparatus associated therewith,and means for unbalancing the magnetic effects of said windings when thecordcircuit is connected with the line whereby the said pole is shiftedor prevented from forming and the said armature is unattracted,substantially as described.

7. In a telephone system, the combination with a signaling device, of aclosed magnetic circuit for said device, means to establish a consequentpole at a point on said magnetic circuit to actuate the signal, andmeans to suitably shift said pole on the magnetic circuit to efi'ace thesignal, substantially as described.

8. In a telephone system, the combination 'with a signal-operatingdevice, of a closed and an open magnetic circuit for said device,electric circuits for the device, and means open magnetic circuit forsaid device, electric circuits for said device, and means to control thecurrent in said electric circuits so as to either include or excludesaid open magnetic circuit in the path of the magnetic flux of thedevice, and a signal controlled by the flux in said open magneticcircuit, substantially as described.

10. In a telephone system, the combination mag.

With a signaling device, of a closed and an I open magnetic circuit forsaid device, means under the control of the subscriber to include saidopen magnetic circuit in the path of magnetic lines of force in thedevice, and means under the control of the operator to exclude said openmagnetic circuit from the path of the lines of force of the device, of asignal adapted to be displayed When the lines of force of the devicepass through the open magnetic circuit and adapted to be efl'aced Whenthe lines of force pass through the closed magnetic circuit,substantially as described.

Signed by me at Chicago, county of Cook, State of Illinois, this 15thday of December, 1902.

WILLIMI W. DEAN.

Witnesses:

ROBERT LEWIS AMEs, GAZELLE BEDER.

